This invention relates to locking mechanisms for doors, and particularly to locking mechanisms that are unlocked using proximity cards and proximity card detection systems. More particularly, the present invention relates to apparatus and methods for detecting proximity cards under low levels of current consumption, then activating higher current-draw assemblies.
According to one aspect of the present invention, a security system comprises a card containing access information, a reader for reading the card, a power source, a locking mechanism, and a first circuit for operating the locking mechanism. The power source is coupled to the first circuit to provide power to the first circuit. The power source is also coupled to a wake-up circuit to provide power to the wake-up circuit. The wake-up circuit detects the presence of an object and enables the reader to ascertain whether the object is the card.
Illustratively according to this aspect of the invention, the power source is coupled to the reader via a switch providing a power supply path and a control line. The power supply path is coupled to the power source and to the reader and the control line is coupled to the wake-up circuit. The wake-up circuit controls the power supply path through the control line to enable the power supply path to supply power to the reader upon detection by the wake-up circuit of the object.
Further illustratively according to this aspect of the invention, the wake-up circuit further comprises a circuit for producing a signal for controlling the switch.
Additionally illustratively according to this aspect of the invention, the wake-up circuit comprises a circuit for determining that electromagnetic energy was first absent, then determining that the electromagnetic energy was present, then determining that the electromagnetic energy was absent again before enabling the reader to ascertain whether the object is the card. The signal enables the power supply path to the reader after the wake-up circuit has determined first the absence, then the presence, then the absence, of the electromagnetic energy.
Illustratively according to this aspect of the invention, the wake-up circuit comprise a circuit for determining that the electromagnetic energy was first absent, then within a first period of time after determining that the electromagnetic energy was first absent determining that the electromagnetic energy was present, then within a second period of time after determining that the electromagnetic energy was present, which second period of time may be of the same duration or a different duration than the first period of time, determining that the electromagnetic energy was absent again before enabling the reader to ascertain whether the object is the card.
Further illustratively according to this aspect of the invention, the wake-up circuit comprises an emitter of electromagnetic energy and a detector of electromagnetic energy.
Additionally illustratively according to this aspect of the invention, the electromagnetic energy emitter and electromagnetic energy detector comprise an infrared emitter and infrared detector, respectively.
According to another aspect of the invention, a method is provided for operating a security system comprising a card containing access information, a locking mechanism, a first circuit for operating the locking mechanism, and a second circuit for detecting the presence of an object and ascertaining whether the object is the card. The method comprises first determining that electromagnetic energy is not being detected by the second circuit, then determining that electromagnetic energy is being detected by the second circuit, then determining that electromagnetic energy is not being detected by the second circuit, and then ascertaining whether the object is the card.
According to this aspect of the invention, the steps of first determining that electromagnetic energy is not being detected by the second circuit, then determining that electromagnetic energy is being detected by the second circuit, then determining that electromagnetic energy is not being detected by the second circuit comprise first determining that electromagnetic energy is not being detected by the second circuit, then within a first period of time after determining that electromagnetic energy is not being detected by the second circuit determining that electromagnetic energy is being detected by the second circuit, then within a second period of time after determining that the electromagnetic energy is being detected by the second circuit, which second period of time may be of the same duration or a different duration than the first period of time, determining that electromagnetic energy is not being detected by the second circuit.
Additionally illustratively according to this aspect of the invention, the security system further comprises a power source coupled to the reader via a switch providing a power supply path and a control line. The power supply path is coupled to the power source and to the reader and the control line is coupled to the second circuit. The method further comprises controlling the power supply path through the control line to enable the power supply path to supply power to the reader upon detection by the second circuit of the object.
Additionally illustratively according to this aspect of the invention, the second circuit comprises a third circuit for detecting the presence of the object and a reader for ascertaining whether the object is the card. The steps of first determining that electromagnetic energy is not being detected by the second circuit, then determining that electromagnetic energy is being detected by the second circuit, then determining that electromagnetic energy is not being detected by the second circuit comprise first determining that electromagnetic energy is not being detected by the third circuit, then determining that electromagnetic energy is being detected by the third circuit, then determining that electromagnetic energy is not being detected by the third circuit, respectively. The step of ascertaining whether the object is the card comprises ascertaining with the reader whether the object is the card.
Further illustratively according to this aspect of the invention, the third circuit comprises an emitter of electromagnetic energy and a detector of electromagnetic energy. The steps of first determining that electromagnetic energy is not being detected by the third circuit, then determining that electromagnetic energy is being detected by the third circuit, then determining that electromagnetic energy is not being detected by the third circuit comprise the steps of first detecting the absence of electromagnetic energy using the detector, then emitting electromagnetic energy using the emitter and simultaneously detecting the emitted electromagnetic energy using the detector, and then detecting the absence of electromagnetic energy using the detector, respectively.
Additionally according to this aspect of the invention, the steps of first determining that electromagnetic energy is not being detected by the third circuit, then determining that electromagnetic energy is being detected by the third circuit, then determining that electromagnetic energy is not being detected by the third circuit comprise the steps of first determining that infrared energy is not being detected by the third circuit, then emitting infrared energy using the emitter and simultaneously determining that infrared energy is being detected by the third circuit, then determining that infrared energy is not being detected by the third circuit.
According to another aspect of the invention, an access system for controlling access to a location secured by a locking mechanism comprises a power source, a wake-up circuit coupled to the power source to detect the presence of a proximity card, and an access control circuit including a proximity card reader coupled to the wake-up circuit.
Illustratively according to this aspect of the invention, the access control circuit is coupled to the wake-up circuit by a switch.
Further illustratively according to this aspect of the invention, the switch comprises a software-controlled switch.
Additionally illustratively according to this aspect of the invention, the wake-up circuit includes an emitter and a detector.
Illustratively according to this aspect of the invention, the emitter and detector comprise an infrared energy emitter and infrared energy detector.
Illustratively according to this aspect of the invention, the emitter and detector comprise an emitter and detector of ambient infrared energy for determining if a proximity card is present.
Alternatively illustratively according to this aspect of the invention, the emitter and detector comprise an ultrasonic energy emitter and ultrasonic energy detector for determining if a proximity card is present.
Alternatively illustratively according to this aspect of the invention, the emitter and detector comprise a magnetic field emitter and a magnetic field detector.
Alternatively illustratively according to this aspect of the invention, the emitter and detector comprise an emitter and detector for detecting electrical coils of a proximity card for determining if a proximity card is present.
Further illustratively according to this aspect of the invention, the wake-up circuit includes a sensor to sense changes in capacitance for determining if a proximity card is present.
Additionally illustratively according to this aspect of the invention, the wake-up circuit includes a sensor to sense changes in inductance for determining if a proximity card is present.
Illustratively according to this aspect of the invention, the wake-up circuit includes a sensor to sense changes in electrical charge for determining if a proximity card is present.
According to another aspect of the invention, a method for controlling access to a location secured by a locking mechanism comprises the steps of detecting a proximity card using a wake-up circuit, transmitting a wake-up signal to an access control circuit, reading card data from the proximity card, and unlocking the locking mechanism when valid card data is read.
Illustratively according to this aspect of the invention, the method further comprises the step of sending card data to the access control circuit.
Further illustratively according to this aspect of the invention, the step of sending card data to the access control circuit comprises sending card data to the access control circuit via a card data signal.
Additionally illustratively according to this aspect of the invention, the method further comprises the step of matching the card data to card data stored within the access control circuit.
Illustratively according to this aspect of the invention, the step of transmitting a wake-up signal to an access control circuit comprises the step of transmitting a wake-up signal to an access control circuit signaling the access control circuit that a proximity card has been detected.
According to another aspect of the invention, an access system for controlling access to a location secured by a locking mechanism comprises a power source, a wake-up switch coupled to the power source to indicate the presence of a proximity card, and an access control circuit including a proximity card reader coupled to the wake-up switch.
According to another aspect of the invention, a method for controlling access to a location secured by a locking mechanism comprises the steps of detecting the change of state of a switch, transmitting a wake-up signal to an access control circuit, reading card data from a proximity card, and unlocking the locking mechanism when valid card data is read.